DTV receiver and method of processing signal in DTV receiver

ABSTRACT

A DTV receiver includes a tuner, a demodulator, a channel equalizer, a sequence detector, and a burst controller. The tuner receives a DTV signal having main data and at least one burst of enhanced data. The demodulator demodulates the DTV signal by performing carrier and time recovery and the channel equalizer equalizes the demodulated signal. The sequence detector detects one or more known data sequences from any one of the received signal and the demodulated signal. The demodulator and the channel equalizer use the detected known data sequences when performing the carrier and timing recover and the channel-equalization, respectively. Lastly, the burst controller supplies power to the tuner, the demodulator, the channel equalizer, and the data detector only during a burst time for each burst of enhanced data for efficient power consumption.

This application claims the benefit of the Korean Patent Application No.10-2005-0096300, filed on Oct. 12, 2005, which is hereby incorporated byreference as if fully set forth herein. This application also claims thebenefit of U.S. Provisional Application No. 60/825,263, filed on Sep.11, 2006, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital telecommunications system,and more particularly, to a DTV receiver and method of processing signalin DTV receiver

2. Discussion of the Related Art

Since the second half of 1998, the United States of America has adoptedan advanced television systems committee (ATSC) VSB (Vestigial Sideband)transmission method as the 1995 standard for digital broadcasting.Presently, the Republic of Korea is also providing broadcast programs byadopting the ATSC 8T-VSB transmission method as the standard forbroadcasting. Accordingly, experimental broadcasting began in May 1995,and a test-broadcasting system began on Aug. 31, 2000.

FIG. 1 illustrates a conventional ATSC 8T-VSB transmitting system. Adata randomizer randomizes MPEG video/audio data that are inputted. AReed-Solomon encoder Reed-Solomon encodes data so as to add a 20-byteparity code. A data interleaver interleaves the data. A Trellis encoderconverts the data from bytes to symbols and, then, Trellis encodes theconverted data. A multiplexer (MUX) multiplexes a symbol column andsynchronization signals, and a pilot inserter adds a pilot signal to thesymbol column. A VSB modulator converts the symbol column to an 8VSBsignal of an intermediate frequency bandwidth. And, a RF converterconverts the VSB-converted signal to an RF bandwidth signal andtransmits the RF bandwidth-converted signal to an antenna.

FIG. 2 illustrates a structure of a general VSB transmission frame.Herein, one frame consists of two fields, wherein each field includesone field synchronization segment and 312 data segments. The 8T-VSBtransmission mode, which is adopted as the standard for digitalbroadcasting in North America and the Republic of Korea, is a systemthat has been developed for the transmission of MPEG video/audio data.However, presently, the technology for processing digital signals isbeing developed at a vast rate, and, as a larger number of thepopulation uses the Internet, digital electric appliances, computers,and the Internet are being integrated. Therefore, in order to meet withthe various requirements of the users, a system that can add video/audiodata through a digital television channel so as to transmit diverseadditional information needs to be developed.

Some users may assume that additional data broadcasting would be appliedby using a PC card or a portable device having a simple in-door antennaattached thereto. However, when used indoors, the intensity of thesignals may decrease due to a blockage caused by the walls ordisturbance caused by approaching or proximate mobile objects.Accordingly, the quality of the received digital signals may bedeteriorated due to a ghost effect and noise caused by reflected waves.However, unlike the general video/audio data, when transmitting theadditional data, the data that is to be transmitted should have a lowerror ratio. More specifically, in case of the video/audio data, errorsthat are not perceived or acknowledged through the eyes or ears of theuser can be ignored, since they do not cause any or much trouble.Conversely, in case of the additional data (e.g., program executionfile, stock information, etc.), an error even in a single bit may causea serious problem. Therefore, a system highly resistant to ghost effectsand noise is required to be developed.

The additional data are generally transmitted by a time-division methodthrough the same channel as the MPEG video/audio data. However, with theadvent of digital broadcasting, ATSC VSB digital television receiversthat receive only MPEG video/audio data are already supplied to themarket. Therefore, the additional data that are transmitted through thesame channel as the MPEG video/audio data should not influence theconventional ATSC VSB receivers that are provided in the market. Inother words, this may be defined as ATSC VSB compatibility, and theadditional data broadcast system should be compatible with the ATSC VSBsystem. Herein, the additional data may also be referred to as enhanceddata or E-VSB data. Furthermore, in a poor channel environment, thereceiving quality of the conventional ATSC VSB receiving system may bedeteriorated. More specifically, resistance to changes in channels andnoise is more highly required when using portable and/or mobilereceivers.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a digital broadcastingsystem and receiving method that substantially obviate one or moreproblems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a digital televisionsystem that is suitable for transmitting additional data and that ishighly resistant to noise.

Another object of the present invention is to provide a digitalbroadcasting system and receiving that can insert known data in aspecific area of the additional data and transmitting the data to atransmitter/receiver, thereby enhancing the receiving quality of thedigital television system.

A further object of the present invention is to provide a digitalbroadcasting system and receiving method for time-division multiplexingand transmitting enhanced data including main data and known data.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adigital television (DTV) receiver includes a tuner, a demodulator, achannel equalizer, a sequence detector, and a burst controller. Thetuner receives a digital television (DTV) signal, in which main data andone or more burst of enhanced data are multiplexed, from a DTVtransmitter. Each burst of enhanced data includes one or more groups ofconsecutive enhanced data packets. Next, the demodulator demodulates theDTV signal by performing carrier and timing recovery, and the channelequalizer channel-equalizes the demodulated DTV signal.

The sequence detector detects one or more known data sequences from anyone of the signal received by the tuner and the demodulated signal. Thedemodulator and the channel equalizer use the detected know datasequences when performing the carrier and timing recovery and thechannel equalization, respectively. Lastly, the burst controllersupplies power to the tuner, the demodulator, the channel equalizer, andthe data detector only during a burst time for each burst of enhanceddata.

The DTV receiver may further include an information detector detectingfirst information which specifies the burst time. In a first example,the information detector detects the first information from a fieldsynchronization segment included in the demodulated signal and providesthe detected first information to the burst controller. Alternatively,the information detector detects the first information from each groupof consecutive enhanced data packets included in the channel-equalizedsignal and provides the detected first information to the burstcontroller. The information detector may further detect secondinformation associated with the known data sequences from thedemodulated signal or from the channel-equalized signal and provide thedetected second information to the sequence detector.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a block view of a general digital broadcasttransmitting system;

FIG. 2 illustrates a structure of a general VSB transmission frame;

FIG. 3 illustrates a block view of a multiplexing device according to anembodiment of the present invention;

FIG. 4 illustrates examples (a) and (b) of a multiplexing method of themultiplexing device shown in FIG. 3;

FIG. 5 illustrates a block view of a digital broadcast transmittingsystem according to an embodiment of the present invention;

FIG. 6 illustrates a block view of a digital broadcast transmittingsystem according to another embodiment of the present invention; and

FIG. 7 illustrates a digital broadcast receiving system according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. In addition,although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meaning of each term lying within.

In the present invention, enhanced data can correspond to such datahaving information such as a program execution file, stock informationand the like or may correspond to video/audio data. And, known data isthe data previously known by agreement between transmitting andreceiving sides. Moreover, main data is the data receivable by aconventional receiving system and includes video/audio data.

The present invention relates to inserting known data known by thetransmitter/receiver in a specific area of an enhanced data packet andtransmitting the processed data packet, so that the processed data isused in the receiver, thereby enhancing the receiving performance of thereceiving system. Most particularly, the present invention relates togrouping at least one enhanced data packet and transmitting at least onedata packet group in burst units from the transmitting end (ortransmitter). When the receiving end (or receiver) receives only theenhanced data, the power is turned on only during the burst section.Thus, by turning the power off during the remaining sections, powerconsumption of the receiver may be reduced. Herein, at least one of onlythe enhanced data packet groups within one burst may be multiplexed, orat least one enhanced data packet group and main data packets may bemultiplexed.

FIG. 3 illustrates a block view of a multiplexing device according to anembodiment of the present invention. The multiplexing device includes anE-VSB pre-processor 301, an E-VSB packet formatter 302, a packetmultiplexer 303, and a scheduler 310. In the multiplexing device havingthe above-described structure, main data are outputted to the packetmultiplexer 303 in transport packet units, and enhanced data areoutputted to E-VSB pre-processor 301. The E-VSB pre-processor 301pre-processes the enhanced data, such as encoding additional errorcorrection, interleaving, and inserting null data, and then outputs thepre-processed enhanced data to the E-VSB packet formatter 302.

Based upon the control of the scheduler 310, the E-VSB packet formatter302 multiplexes the pre-processed enhanced data and the pre-definedknown data, thereby configuring a group. The data within the group arethen divided into 184-byte unit enhanced data packets, and a 4-byte MPEGheader is added to the beginning of the enhanced data packet, therebyoutputting a 188-byte enhanced data packet (i.e., a MPEG compatibilitypacket). In other words, one enhanced data packet group includes aplurality of consecutive enhanced data packets. The output of the E-VSBpacket formatter 302 is inputted to the packet multiplexer 303. Thepacket multiplexer 303 time-division multiplexes the main data packetand the enhanced data packet in transport stream (TS) packet units andoutputs the multiplexed TS packet. More specifically, the scheduler 310generates and outputs a control signal so that the packet formatter 302can multiplex the enhanced data and the known data. The scheduler 310also generates and outputs a control signal, so that the packetmultiplexer 303 can multiplex the main data packet and the enhanced datapacket. Accordingly, the packet multiplexer 303 receives the controlsignal, thereby multiplexing and outputting the grouped main data packetand enhanced data packet to TS packet units.

At this point, based upon the control of the scheduler 310, atransmission parameter for multiplexing the packet formatter 302 and thepacket multiplexer 303 may be multiplexed along with the multiplexing ofthe enhanced data and the known data. Alternatively, a transmissionparameter may also be multiplexed and outputted when the main datapacket and the enhanced data packet group are multiplexed by the packetmultiplexer 303. Furthermore, the transmission parameter may also beinserted in a reserved area of the ATSC VSB field synchronizationsegment and then transmitted. More specifically, the transmissionparameter may be inserted in a pre-decided position (or place) of aparticular group and then transmitted, and/or be inserted in a reservedarea of the field synchronization segment and then transmitted. Herein,the transmission parameter may include information of the length of acurrent burst, information indicating a starting point of a next burst,the place in which the groups exists within the burst and the length ofeach group, the time starting from the current group to the next groupwithin the burst, and information on the known data. Either apredetermined value or a real-time variable value may be used for eachof the various parameters.

FIG. 4 illustrates examples of a multiplexing method of the multiplexingdevice. Referring to FIG. 4, a group consists of a plurality ofconsecutive enhanced data packets, wherein the data packet groups aregrouped (or gathered) to form a burst. Herein, the consecutive enhanceddata packets are multiplexed in group units in order to maximize thereceiving performance of the receiving system. More specifically, whenthe known data inserted by the E-VSB packet formatter 302 are Trellisencoded by the digital broadcast transmitting system, so as to befinally transmitted. Herein, the known data are consecutivelytransmitted, thereby maximizing the receiving performance of thereceiving system.

If the length of the enhanced data packet group (i.e., the number ofenhanced data packets within the group) is too long (or large), aproblem of compatibility may occur with the conventional ATSC digitalbroadcast receiver which receives the main data packet(s). Morespecifically, the conventional ATSC digital broadcast receiver refers toa packet identifier (PID) of the enhanced data packet and deletes (ordiscards) the enhanced data packet accordingly. However, if a main datapacket is not received for a long period of time, a problem may occur inthe controlling of a buffer. Therefore, according to an embodiment ofthe present invention, enhanced data packets having a length equal to orshorter than a predetermined length are multiplexed in group units, andthe multiplexed data packet group is multiplexed with a main data packetwithin a burst and then outputted.

Furthermore, referring to FIG. 4, a next burst time (NBT) signifies atime starting from each enhanced data packet group within a currentburst to the starting time of the following (or next) burst. In thepresent invention, a next burst time (NBT) is inserted in each groupwithin the current burst and then transmitted. Herein, the NBT is set tobe inserted in a pre-decided area of the corresponding group. Such NBTis decided in the scheduler 310 and provided to the E-VSB packetformatter 302. The E-VSB packet formatter 302 then inputs the NBT in aspecific area of the enhanced data packet group, which is thenoutputted. As shown in FIG. 4, the NBT decreases as it proceeds from G1of the current burst (burst 1) to G2 and G3 (i.e.,NBT_(G1)>NBT_(G2)>NBT_(G3)). At this point, the NBT is repeatedlyinserted within each group in order to allow the receiver to identifythe NBT by receiving of another group even when an error occurs duringthe reception of the corresponding group.

FIG. 5 illustrates a block view of a digital broadcast transmittingsystem according to an embodiment of the present invention, wherein themultiplexing device of FIG. 3 is applied. The digital broadcasttransmitting system includes an E-VSB pre-processor 501, an E-VSB packetformatter 502, a packet multiplexer 503, a data randomizer 504, ascheduler 505, an E-VSB post-processor 510, a Reed-Solomon (RS) encoder521, a data interleaver 522, a Trellis encoder 523, a backwardcompatibility processor 524, a frame multiplexer 525, and a transmitter530. Since the operation of each of the E-VSB pre-processor 501, theE-VSB packet formatter 502, the packet multiplexer 503, the datarandomizer 504, and the scheduler 505 has already been described indetail, the description of the same will be omitted for simplicity.

The data outputted from the packet multiplexer 503 passes through thedata randomizer 504 and are outputted to the E-VSB post-processor 510.

Herein, the E-VSB post-processor 510 includes a Reed-Solomon (RS)encoder 511, a data interleaver 512, an E-VSB convolutional encoder 513,a data deinterleaver 514, and a RS byte remover 515. The RS encoder 511RS-codes the data outputted from the data randomizer 504. Thereafter,the RS encoder 511 adds 20-byte parity data and outputs the data to thedata interleaver 512.

The data interleaver 512 interleaves the data packet having the paritydata bytes added thereto and being outputted. Thereafter, the datainterleaver 512 outputs the interleaved data packet to the E-VSBconvolutional encoder 513. Herein, the output data of the datainterleaver 512 are outputted to the E-VSB convolutional encoder 513.Then, the E-VSB convolutional-encoded data pass through the datainterleaver 514 and are outputted to the RS byte remover 515, therebyremoving (or deleting) the 20-byte parity data. The E-VSB convolutionalencoder 513 converts the inputted bytes to symbols. Subsequently, E-VSBconvolutional-encoding is performed only on the enhanced data symbols,which are then converted back to bytes from symbols so as to beoutputted. More specifically, the E-VSB convolutional encoder 513outputs data without modifying the data when the output of the datainterleaver 512 is the main data, or when the output of the datainterleaver 512 is the known data that were inserted in the enhanceddata packet. Further, the E-VSB convolutional encoder 513 also outputsthe MPEG header byte added by the E-VSB packet formatter and the RSparity byte added to the enhanced data packet by the RS encoder 511without modifying the corresponding data.

The RS byte remover 515 removes the 20-byte parity data, which wereadded to the corresponding data by the RS encoder 511, and outputs theparity-removed input data to the RS encoder 521. The RS encoder 521RS-codes the input data so as to add the 20-byte parity data once againto the input data. Then, the RS encoder 521 outputs the parity-addeddata to the data interleaver 522. The data interleaved by the datainterleaver 522 are inputted to the trellis encoder 523. The trellisencoder 523 trellis-encodes the inputted 2 bits to 3 bits and outputsthe trellis-encoded data (i.e., 3 bits) to the frame multiplexer 525. Inorder to make the data outputted from the trellis encoder 523 as theknown data defined from the transmitting/receiving ends, a memory withinthe trellis encoder 523 needs to be initialized with respect to theknown data inserted in the E-VSB packet.

At this point, initialization is performed by a new set of data and notby the input data. Therefore, a new set of RS parity data should becreated and be replaced with the initial parity data. More specifically,this operation is performed by the backward-compatibility processor 324.The output of the trellis encoder 523 is inputted to the framemultiplexer 525. Then, the frame multiplexer 525 inserts field andsegment synchronization signals to the output data of the trellisencoder 523 and outputs the data to the transmitter 530. Herein, thetransmitter 530 includes a pilot inserter 531, a VSB modulator 533, anda radio frequency (RF) converter 534. Since this structure is similar tothe digital television transmitter of FIG. 1, a detailed description ofthe same will be omitted for simplicity. As another embodiment of thepresent invention, the multiplexing device of FIG. 5 may be applied inthe digital television transmitter, thereby being capable ofmultiplexing and transmitting the enhanced data packet and the main datapacket.

FIG. 6 illustrates a block view of a digital broadcast transmittingsystem according to another embodiment of the present invention, whereinthe multiplexing device of FIG. 3 is applied. The digital broadcasttransmitting system includes an E-VSB pre-processor 601, an E-VSB packetformatter 602, a packet multiplexer 603, a data randomizer 604, ascheduler 605, a RS encoder/parity place holder inserter 606, a datainterleaver 607, a byte-symbol converter 608, an E-VSB symbol processor609, a known data generator 610, a symbol-byte converter 611, anon-systematic RS encoder 612, a Trellis encoder 613, a framemultiplexer 614, and a transmitter 620.

The E-VSB packet formatter 602 of FIG. 6 decides the known data placeholder in which the known data within the packet is to be inserted.Then, the E-VSB packet formatter 602 inserts a null data in the decidedknown data place holder, so as to be multiplexed with the output data ofthe E-VSB pre-processor 601, thereby configuring a group. Subsequently,the data within the group are divided into a 184-byte unit enhanced datapackets. Thereafter, a 4-byte MPEG header byte is added to the beginningof the enhanced data packet, thereby outputting a 188-byte enhanced datapacket (i.e., a MPEG compatibility packet). In other words, one enhanceddata packet group includes a plurality of consecutive enhanced datapackets.

Since the operation of each of the packet multiplexer 603 and thescheduler 605 has already been described in detail in the operation ofthe packet multiplexer and scheduler of FIG. 3, the description of thesame will be omitted for simplicity.

The output of the packet multiplexer 603 is randomized by the datarandomizer 604. Then, the randomized data are inputted to theReed-Solomon (RS) encoder/parity place holder inserter 606. The RSencoder/parity place holder inserter 606 processes the randomized datawith either a systematic RS-coding process or a non-systematic parityplace holder insertion process. More specifically, when the 187-bytepacket that is outputted from the data randomizer 604 corresponds to themain data packet, the RS encoder/parity place holder inserter 606performs the same systematic RS-coding as the conventional ATSC VSBsystem, thereby adding 20-byte parity data at the end of the 187-bytedata.

Conversely, when the 187-byte packet that is outputted from the datarandomizer 604 corresponds to the enhanced data packet, a position (orplace) of a parity data byte within the packet is decided so that the 20parity data bytes are outputted from the output terminal of the datainterleaver 607 later than the 187 data bytes. Then, a null data byte isinserted in the decided parity byte position (or place). Further, the187 data bytes received from the data randomizer 604 are sequentiallyinserted in the remaining 187 byte positions.

The null data byte is given an arbitrary value, and such null data bytevalue is substituted with the parity value calculated by thenon-systematic RS encoder 612 in a later process. Accordingly, the roleof the null data byte is to ensure the parity byte position (or place)of a non-systematic RS code. The non-systematic RS code is used for theenhanced data packet for the following reason. When the value of theenhanced data is changed by the E-VSB symbol processor 609, which willbe described in detail in a later process, the RS parity should berecalculated. And so, the parity bytes should be outputted from the datainterleaver 607 output terminal later than the data bytes.

The output data of the RS encoder/parity place holder inserter 606 areoutputted to the data interleaver 607. Then, the data interleaver 607interleaves and outputs the received data. At this point, the datainterleaver 607 receives a RS parity byte that is newly calculated andoutputted by the non-systematic RS encoder 612 and, then, substitutesthe newly received RS parity byte for the non-systematic RS parity placeholder which is not yet outputted. More specifically, the datainterleaved 187 information bytes are first outputted. Thereafter, the20 parity place holders in which a null data byte is respectivelyinserted are replaced with the newly calculated 20 RS parity bytes andthen outputted.

Each data byte outputted from the data interleaver 607 is converted into4 symbols by the byte-symbol converter 608, which are then outputted tothe E-VSB symbol processor 609. Herein, one symbol consists of 2 bits.Additionally, the known data sequence generated (or created) from theknown data generator 610 is also outputted to the E-VSB symbol processor609. The E-VSB symbol processor 609 receives the data outputted from thebyte-symbol converter 608 and the known data symbol generated from theknown data generator 610, processes the received data with a pluralityof processing steps, and then outputs the processed data to the trellisencoder 613 and the symbol-byte converter 611, respectively. Forexample, when the data that are outputted from the byte-symbol converter608 correspond to a known data place holder in which null data areinserted, the E-VSB symbol processor 609 selects the known datagenerated from the data generator 610 instead of the known data placeholder. Then, the E-VSB symbol processor 609 outputs the selected knowndata to the trellis encoder 613 and the symbol-byte converter 611.

In the portion where the known data symbol begins, the E-VSB symbolprocessor 609 generates a data symbol that initializes a memory of thetrellis encoder 613 to a predetermined state. Thereafter, the E-VSBsymbol processor 609 outputs the generated data symbol instead of theknown data symbol. In order to do so, the value of the memory in thetrellis encoder 613 should be received from the E-VSB symbol processor609. The trellis encoder 613 is initialized at the beginning of theknown data sequence because, even though the known data sequence isinputted as the input of the trellis encoder 613, a plurality of outputsequences may be outputted depending upon the memory state of thetrellis encoder 613. Therefore, when the known data are inputted afterthe memory state of the trellis encoder 613 is initialized to apredetermined value, the known data output sequence may be obtained fromthe output of the trellis encoder 613.

The trellis encoder 613 pre-codes the data that are inputted as theupper bit among the output symbol of the E-VSB symbol processor 608, andtrellis-encodes the data that are inputted as the lower bit. Thereafter,the pre-coded data and the trellis-encoded data are outputted to theframe multiplexer 614. Meanwhile, the E-VSB symbol processor 609receives the symbol consisting of 2 bits, processes the received symbolwith a plurality of process steps, and outputs the processed symbol.Therefore, the symbol should be converted back to data bytes from thesymbol-byte converter 611 so that the non-systematic RS encoder 612 canrecalculate the RS parity from the output of the E-VSB symbol processor609. The non-systematic RS encoder 612 calculates the 20-byte RS parityfor the data packet configured of 187 information bytes and outputs thecalculated RS parity to the data interleaver 607.

The frame multiplexer 614 inserts 4 segment synchronization symbols ineach 828 output symbols of the trellis encoder 613, thereby configuringa data segment having 832 data symbols. More specifically, one fieldsynchronization segment is inserted in each 312 data segments, so as toconfigure one data field, which is then outputted to the transmitter620. Herein, the transmitter 620 includes a pilot inserter 621, a VSBmodulator 622, and a radio frequency (RF) converter 623.

Meanwhile, the enhanced data packet is transmitted in burst units so asto allow the power of the receiver to be turned on only during the burstperiod when using a receiver that only receives the enhanced data. Thischaracteristic is advantageous in portable or mobile receivers whichrequire low power consumption.

FIG. 7 illustrates a digital broadcast receiving system according to anembodiment of the present invention. Referring to FIG. 7, the digitalbroadcast receiving system broadly includes a receiver 700 and a burstcontroller 800, the burst controller 800 controlling the power supply tothe receiver 700. The receiver 700 includes a tuner 701, a demodulator702, an equalizer 703, a known data (or sequence) detector 704, aViterbi decoder 705, a data deinterleaver 706, a RS decoder/RS parityremover 707, and a derandomizer 708. The receiver 700 also includes amain data packet remover 709, an E-VSB packet deformatter 710, aparameter detector 711, and an enhanced data processor 712.

The tuner 701 tunes the frequency of a particular channel. Subsequently,the tuner 701 down-converts the tuned frequency and outputs the tunedchannel frequency to the demodulator 702 and the known data detector704. The demodulator 702 performs carrier recovery and timing recoveryof the tuned channel frequency, and outputs the processed channelfrequency to the equalizer 703 and the known data detector 704. If thetransmission parameters corresponding to the known data, the enhanceddata packet group, and the burst are included and transmitted in thefield synchronization segment, the information is outputted to theparameter detector 711. The equalizer 703 performs compensation for anychannel distortion included in the demodulated signal and outputs thecompensated signal to the Viterbi decoder 705.

At this point, the known data detector 704 detects the known data symbolcolumn, which has been inserted by the transmitting end, from the outputdata of the tuner 701 and/or the demodulator 702. Then, the known datadetector 704 outputs the detected known data symbol column to thedemodulator 702 and the equalizer 703. When the demodulator 702 uses theknown data during the timing recovery or the carrier recovery, thedemodulating performance may be enhanced. Similarly, when the equalizer703 uses the known data, the equalization performance may be enhanced.The Viterbi decoder 705 Viterbi encodes the data outputted from theequalizer 703 and converts the Viterbi encoded data to bytes.Thereafter, the converted data are outputted to the data deinterleaver706. The data deinterleaver 706 performs an inverse process of the datainterleaver of the transmitting system and outputs the deinterleaveddata to the RS decoder/RS parity remover 707.

If the received data packet is the main data packet, the RS decoder/RSparity remover 707 RS decodes the received main data packet.Alternatively, if the received data packet is the enhanced data packet,the RS decoder/RS parity remover 707 removes the parity bytes withoutperforming RS decoding. At this point, the operation of removing theparity bytes may vary depending upon the structure of the digitalbroadcast transmitting system applied in the present invention. Forexample, if the enhanced data packet is transmitted from the digitalbroadcast transmitting system shown in FIG. 5, the last 20 bytes of thecorresponding data packet are removed. On the other hand, if theenhanced data packet is transmitted from the digital broadcasttransmitting system shown in FIG. 6, the 20 bytes of non-systematic RSparity place holder placed in between data packets are removed.Thereafter, the parity-removed data packet is outputted to thederandomizer 708.

The derandomizer 708 performs an inverse process of the randomizer ofthe transmitting system on the output of the RS decoder/RS parityremover 707. Thereafter, the derandomizer 708 inserts the MPEGsynchronization byte in the beginning of each packet, thereby outputtingthe data in 188-byte packet units. The output of the derandomizer 708 issimultaneously outputted to the main MPEG decoder (not shown) and to themain data packet remover 709. Herein, the main MPEG decoder only decodesthe packet(s) corresponding to the main MPEG. If the packet ID is a nullpacket ID (i.e., the enhanced data packet), the main MPEG decoder doesnot perform the decoding process.

In the meantime, the main data packet remover 709 removes the 188-bytemain data packet from the data outputted from the derandomizer 708 andoutputs only the enhanced data packet to the E-VSB packet deformatter710. The E-VSB packet deformatter 710 removes the MPEG header from theenhanced data packet outputted by the main data packet remover 709,thereby obtaining a 184-byte data packet. Subsequently, the E-VSB packetdeformatter 710 configures a group having a pre-decided size by groupingthe 184-byte data packets. Thereafter, the E-VSB packet deformatter 710removes the known data or known data place holder(s) that have beeninserted by the transmitting system (or transmitter) for demodulationand equalization processes. Furthermore, if the transmission parameterscorresponding to the known data, the enhanced data packet group, and theburst are inserted in a pre-determined place in each group and thentransmitted, the E-VSB packet deformatter 710 outputs such informationto the parameter detector 711. In this case, the data having the knowndata or known data place holder(s) removed are configured of E-VSBpre-processed enhanced data and a transmission parameter includinginformation on a group and a burst.

The parameter detector 711 detects the information on the known datafrom the transmission parameter that has been multiplexed in the fieldsynchronization segment and/or the data group and also detects theinformation on the burst. Then, the parameter detector 711 outputs thedetected information on the known data to the known data detector 704and the detected information on the burst to the burst controller 800.At this point, each set of the known data is inserted differently ineach packet within the group. Therefore, the information on the groupobtained after the E-VSB packet deformatting is detected, so as toreceive information on the known data from the known data detector 704.Thus, the received information may be used for detecting the known data.Furthermore, if the known data are inserted in a particular place (orposition) by a particular method, the known data are detected prior toextracting the information on the group, so as to be used in the fordemodulation and equalization processes. The enhanced data processor 712performs an inverse process of the E-VSB pre-processor of thetransmitting system on the output of the E-VSB packet deformatter 710,thereby performing a final output of the enhanced data.

Depending upon the burst information that is inputted, the burstcontroller 800 supplies power to the current burst section so that thereceiver 700 can be operated. On the other hand, the burst controller800 shuts down the power supply to the section starting from the end ofthe current burst section to the next burst section, wherein theenhanced data that are to be received do not exist. Thus, the energyconsumed by the receiver may be reduced. More specifically, when only aparticular set of enhanced data is to be received in a system having themain data and the enhanced data multiplexed and transmitted thereto, theenergy consumed within the section having no desired set of enhanceddata is largely reduced. Accordingly, when only the enhanced data arereceived, the burst controller 800 supplies the power to the receiver700 during the burst section and shut shuts down the power supply to thereceiver 700 during the remaining sections, thereby reducing the powerconsumption of the receiver. More specifically, data are received onlyin the burst having the group configured of the enhanced data includedtherein, whereas the power is not supplied (or shut down) in apre-determined area of the receiver during the non-burst section, so asto reduce excessive power consumption.

As described above, the digital broadcasting system, method, and datastructure according to the present invention have the followingadvantages. Herein, the digital broadcasting system is highly protectedagainst (or resistant to) any error that may occur when transmittingadditional data through a channel, and the digital broadcasting systemis also highly compatible to the conventional VSB system. The presentinvention may also receive the additional data without any error even inchannels having severe ghost effect and noise. Additionally, byinserting known data in a specific area of the data area andtransmitting the processed data, the receiving performance of thereceiving system liable to a frequent change in channel may be enhanced.Furthermore, the present invention is even more effective when appliedto mobile and portable receivers, which are also liable to a frequentchange in channel and which require protection (or resistance) againstintense noise.

Finally, by grouping a plurality of consecutive enhanced data packetsand transmitting the grouped packets, the receiving performance of thereceiving system may be enhanced. More specifically, by transmitting atleast one group in burst units, the performance of a receiving systemreceiving only the enhanced data. The transmission of the groupedpackets transmitted in burst units is even more effective when appliedto mobile and portable receivers, which are also liable to a frequentchange in channel and which require protection (or resistance) againstintense noise.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A DTV receiver comprising: a tuner receiving a DTV signal having maindata and at least one burst of enhanced data, each burst of enhanceddata including at least one group of consecutive enhanced data packets,a demodulator demodulating the DTV signal by performing carrier andtiming recovery; a channel equalizer channel-equalizing the demodulatedDTV signal; a sequence detector for detecting one or more known datasequences from any one of the received DTV signal and the demodulatedDTV signal, wherein the demodulator and the channel equalizer use thedetected known data sequences when performing the carrier and timingrecovery and the channel equalization, respectively; and a burstcontroller supplying power to the tuner, the demodulator, the channelequalizer, and the data detector only during a burst time for each burstof enhanced data.
 2. The DTV receiver of claim 1, further comprising aninformation detector detecting first information which specifies theburst time from the demodulated signal and providing the detected firstinformation to the burst controller.
 3. The DTV receiver of claim 2,wherein the information detector detects the first information from afield synchronization segment included in the demodulated signal.
 4. TheDTV receiver of claim 2, wherein the information detector furtherdetects second information associated with the known data sequences fromthe demodulated signal and provides the detected second information tothe sequence detector.
 5. The DTV receiver of claim 1, furthercomprising an information detector detecting first information whichspecifies the burst time from the channel-equalized signal and providingthe detected first information to the burst controller.
 6. The DTVreceiver of claim 5, wherein the information detector detects the firstinformation from each group of consecutive enhanced data packetsincluded in the channel-equalized signal.
 7. The DTV receiver of claim5, wherein the information detector further detects second informationassociated with the known data sequences from the channel-equalizedsignal and provides the detected second information to the sequencedetector.
 8. The DTV receiver of claim 5, wherein the first informationindicates a time between each group of consecutive enhanced data packetsincluded in a current burst of supplemental data and a next burst ofenhanced data.
 9. The DTV receiver of claim 5, wherein the firstinformation indicates a length of a current burst of supplemental data.10. The DTV receiver of claim 5, wherein the first information indicatesa location and length of each group of consecutive enhanced datapackets.
 11. A method of processing a signal in a DTV receiver, themethod comprising: receiving a DTV signal having main data and at leastone burst of enhanced data, each burst of enhanced data including atleast one group of consecutive enhanced data packets; demodulating theDTV signal by performing carrier and timing recovery; channel-equalizingthe demodulated DTV signal; detecting one or more known data sequencesfrom any one of the received DTV signal and the demodulated signal,wherein the signal modulation and channel-equalization of the DTV signalare performed using the detected known data sequences; and supplyingpower to the DTV receiver only during a burst time for each burst ofenhanced data.
 12. The method of claim 11, further comprising detectingfirst information specifying the burst time from the demodulated signal.13. The method of claim 12, wherein the first information is detectedfrom a field synchronization segment included in the demodulated signal.14. The method of claim 12, further comprising detecting secondinformation associated with the known data sequences from thedemodulated signal.
 15. The method of claim 11, further comprisingdetecting first information specifying the burst time from thechannel-equalized signal.
 16. The method of claim 15, wherein the firstinformation is detected from each group of consecutive enhanced datapackets included in the channel-equalized signal.
 17. The method ofclaim 15, further comprising detecting second information associatedwith the known data sequences from the channel-equalized signal.
 18. Themethod of claim 15, wherein the first information indicates a timebetween each group of consecutive enhanced data packets included in acurrent burst of supplemental data and a next burst enhanced data. 19.The method of claim 15, wherein the first information indicates a lengthof a current burst of supplemental data.
 20. The method of claim 15,wherein the first information indicates a location and length of eachgroup of consecutive enhanced data packets.